Spark-plug.



n. BREHMEYER.

' SPARK PLUG.

APPLICATION FILED AUGJS. "16.

1,258,186, mm Mai. 5. i91&

der.

UNITED STATES PATENT OFFICE."

KERRY BBEHMEYEK, 0F PRINCETON, NEW JERSEY.

To all whom it may concern: I

'Be it known that I, HENRY Bnnnunrna, a citizen-of the United-States,residing at Princeton, countyof Mercer, and State of New Jersey, haveinvented certain new and useful Improvements in Spark-Plugs, of

which the followin is a specification.

This invention re ates to improvements in spark plugs, andhas for itsgeneral object to provide a construction which will render those arts ofthe lug which are exposed direct y to the action of the gases inexploding, easilyaccessible when occasion rc--- 'quires that the saidparts be inspected or cleaned. And a further object is to provide meansfor preventing short circniting through the plug. And to these ends theinvention resides in adapting the insulator and the casing therefor tocooperate so as to leave exposed a generous portion of the inner end ofthe insulator, in providing a scraper for the ex osed inner end portion'of the insulator an in adapting such scraper to be 0 rated by theexplosion of the gases when t ese are ignited in the firing chamber.-

Other objects will appear and be better 'understood from that embodimentof my invention of which the following is a speci fication, referencebeing had to the accom panying drawings forming part hereof and Figure1, is a detail showing the casing in vertical lo itudinal section andthe insulator partly 1n section and partly in side elevation. g

Fig, 2, is a detail sectional plan tesen through the exposed inner endportion of the insulator and-showing the scraper.

a Inthe'drawingsW indicates the plug,

5 of which-is formed of metal 4 the casing and-has what will'besubsequently termed its inner end portion 6 screw threaded, and itsouter end portion somewhat enlar ed and polygonal in-contour asindicated by The screw threaded portion 6, screws into the usual o ningin the wall of an engine cylnr I der an the polygonal outer end portion7 gerovides a surface onto which a wrench may readily adjusted in theactjof attaching the plu to or'detaching it from the cylin ,The bore ,8of the sleeve extends from the. inner end thereof to approximately themiddle oounterred portion 9. The presence of th' counter-bored portion 9provides an 1nahoulder 1Q,at' the middleportion of SPABKrPLUG.

Specification 01 Letters Patent.

in the insulator andrgr e inner end portion 23 ortion where itterminates in athe sleeve. The insulator 11 extends through PatentedMar. 5, 1918. Application filed August 10, me, Serial mi. 115,113.

the sleeve and between its ends the said insulator has a c lindricalenlargement 12.

which correspon in diameter approximately to that of the counter-boredportion 9, m which it is disposed and arranged between the shoulder 10and the lock nut 13 which is screwed in o the countenbored portion 9.Gaskets 1 are interposed between the adjacent surfaces of theenlargement 12 v the lock nut 13 and the shoulder 10, an

the lock nut is adjusted so as to coiiperate sponds approximately indiameter to the Thus it will be seen that the bore thereof. portion 16is sufficiently thick togive the stability reguired of an insulator in adevice of this kin The insulator 11 has a longi-, tudinal bore 17 inwhich is dis the electrode 18. The outer end portion of the electrode 18extends beyond the correspond ing end ortion of the insulator and isscrew threaded as indicated at 19. A binding nut 20 is-screwed onto theates to secure the terminal of the electrical portion 19 andoperconductor or wire to the projecting end portion of the electrode 18.

The inner end of the electrode 18 is pro vided with a substantiallyspherical aha head 21'whichis disposed in coo; tarbored inner endportion 22' of the insulator.

And the said counter-bored portion 22 18 l0 lproportioned with respectto the size of the end that the same 15 practically housed within thecounter-bore.

With this construction it is obvious that the electrode pre scnts but aminimum of surface to be operated upon when it is found necessa toremove soot or carbon therefrom. T e head 21 moreover is adapted to coiicrate with the binding nut 20 to tighten t e electrode event leakagethrough the bore thereof. of the insulator is relatively thin ascompared with the outer end portion 16 and fits nicelywithin the bore 8'of the casin 5. A considerable length of the inner en portion 23 is exosed and extends beyond the inner end 0 thecasin 5. This con- 'structionpermits of inspecting orcleaning of the inner when occasion requires andwithout requiring removal from the casing that portion of the insulatorwhich is exposedvto the flame of the gases in exploding. A finger orelectrode 2'; is secured to the inner end of cas- 5 and has its free endportion bent or 0 erwise suitably disposed so as to co'o'perate with thehead 21 of the electrode 20 to provide an intervening space whichconstitutes the usual spark gap. 7

It will now be noted that by reason of the Ian h of the inner ortion 23and the ex ose extension there-o the said s ark gap wi 1; when the In isconnected to e usual t pe of cylin er e disposed well within theexplosion chamber with the resultthat when the mass of explosive mixtureis comressed in the firing chamber the s ark will 1 ite such mass at thecentre portion t ereof.

Manifestly the exposed extension of the inner portion 23 of theinsulator and the finger or electrode 24 will present surfaces ontowhich carbon will readily deposit.- T-herefore and in order to prevent arapid accumulation of carbon on these parts a scra or 25 in the form ofa ring arranged on t e ex osed extension of the inner portion 23 o theinsulator'and a recess 26 is formed in the scraper which receives thefinger or electrode 24; The scraper is made relativel narrow so that itWlll have an a precia le amount ofsliding movement on t e ex' osedextension on the inner portion 23 an on the finger or electrode 24,ja nda stop 27 arranged 1n a groove 28 near the end ortion 3 is rovided forpreventing disp aceme'nt of t e scraper from the insulator. When thespark'plug is con: nected to a cylinder and arranged in an upri htposition the scraper 25 issupported' by t e stop 2:? so that when acharge of combustible mixture s exploded at a point below the scraper,the ex los'ion will cause the scraperto ascend un it strikes against theinner end of casing 5; After the explosioi of the mixture the scra orwill descend until itstrikes the stop. 2 Thus it will August 1916'.

be seen that the semi er reciprocates on the insulator and electr e 24an by this action operates to prevent the relative] ra id formation of afilm or coating 0 car on tween the electrodes and the casing 5 with, theresult that short circuiting ofi the. current through the plug will beprevented. It is obvious that the scraper 25 niay be modified sodas notto'en age electrode 24 and thereby operate on e exposed extension only.I What is claimed as new is:

as I

1. In a spark plug the combination of a" .casing, an insulator disposedtherein and having one end portion exposed and extendcasing andextending beyond the end thereof, said insulator being provided with alongitudinal bore the inner end. of which terminates in'a-counter-boreand further having an intermediately disposed enlargement arranged inthe counter-bored portion of the casing and supported b the shoulder, anelectrode arran d in e bore of the insulator and having in its inner andahead disposed in the counterbore ,ofthe insulator,

a second electrode connected to the casing and used in operativerelation to the head 0 the first namedelectrode, a lock nut surroundingthe insulator and disposed in the casing and a scraper alidingly mountedon the extending inner end portion of tll gdinsulator and on the secondnamed elect e. V

In testimony whereof, I have name to thisspecification', this sign ed dug nmisr BREBMEYEI'I. I

